Wildfires, climate change ensure more bad air days are...

1of2The Golden Gate Bridge is consumed in fog and smoke on Sunday, July 1, 2018 in San Francisco, Calif. Air quality in and around San Francisco has been visibly affected by the fires through the weekend.Photo: Liz Moughon / The Chronicle

Orange-hazed skies and afternoons that reek of campfire smoke are becoming as emblematic of summer in the Bay Area as fog-banked Augusts — only with more hacking coughs and burning, watery eyes.

In this new era of prolonged, intense wildfire seasons brought on predominantly by climate change, residents up and down the West Coast can probably expect long months of poor air quality that could have short- and long-term effects on their heart and lung function, say experts in pollution and public health.

“There’s so much acreage affected by wildfires in so many different places in Northern California,” said Dr. John Balmes, who studies the health effects of air pollutants at the Human Exposure Laboratory at UCSF. “This is a new normal. We’re going to see these kinds of extended bad air days because of wildfire smoke.”

Last year, he noted, residents up and down the state experienced some of the worst air quality conditions from wildfires since scientists have studied the phenomenon. This year, more than three times as much acreage has burned than at the same point in 2017 — and the state hasn’t even reached the traditional peak of the fire season.

In other words: There are probably many more gross, smoky days coming.

Air quality in the Bay Area on Friday was unhealthy for people who are sensitive to pollution, including people with preexisting respiratory illnesses like asthma, children and seniors, according to the Bay Area Air Quality Management District.

Conditions were expected to improve somewhat on Saturday, though particulate measures were to remain above what is widely considered acceptable levels. Parts of the Bay Area, including the North Bay, were forecast to remain above acceptable levels through early next week.

The air-quality index, a number that takes into account several types of pollutants, was hovering around 100 in the Bay Area on Friday, and expected to drop to about 70 to 90 over the weekend. A healthy level is 50 or lower; the worst level is 500.

“We’re definitely seeing really high spikes of fine particulate in the summertime as a result of these wildfires, and this is not something we saw 10 years ago,” said Aaron Richardson, a spokesman for the air quality district.

Much of the smoke in the Bay Area is from the massive Mendocino Complex fire burning north of the Bay Area. But it’s more than just the local fires, Richardson said: “It’s from a whole host of fires. It’s coming all the way down from British Columbia and throughout the Northwest. It’s an unexpected phenomenon.”

Air quality in California is always a seasonal issue, split broadly between the summer and the winter months. But in the past, it was ozone emissions, not pollution from smoke, that affected air quality in the summer. Smoke pollution tended to occur in the winter, when people were more likely to burn wood in their fireplaces or stoves, Richardson said.

Occasionally a major fire would cause some temporary smoke pollution in the summer, he said. But it wasn’t even an annual issue, necessarily. Over the past two or three years, though, there have been multiple wildfires every summer or fall, and they tend to burn up much more acreage.

The result is protracted periods of heavy smoke that sometimes affects regions hundreds of miles from the worst of the blazes.

Pollution from wildfires is different than the usual summertime pollution of increased ozone emitted by cars, industrial plants, refineries and other sources. With smoke pollution, the risk is from the invisible, noxious particulates in the air that are easily inhaled and can make their way deep into the lungs.

“This has been a tough season for a lot of my patients, especially the patients with preexisting lung conditions like emphysema, COPD, asthma,” said Dr. Thomas Dailey, chief of pulmonary medicine at Kaiser Permanente in Santa Clara. “People are feeling more tightness in their chest, feeling more difficulty breathing.”

Children, he added, are particularly vulnerable because their lungs are still developing, and because they often breathe faster, and through their mouths, exposing them to even more particulate matter.

Dailey and other doctors recommend that anyone with respiratory problems stay inside as much as possible on days when particulate measures reach unhealthy levels of 100 or more. If they must go outside, they should consider wearing an N95 mask designed to filter out small particles.

The health effects on people who are otherwise healthy aren’t clear, said Balmes, the expert at UCSF. Because repeated exposure to wildfire smoke among the general public is a relatively new phenomenon, it hasn’t been well studied.

Scientists will sometimes compare pollution levels from wildfire smoke to the heavy pollution that clogs skies in parts of China and India, where studies have found increased rates of heart and lung disease and some cancers. But no one knows for sure if the different pollutants cause similar health problems, Balmes said.

“I ran outside this morning because I didn’t look at what the air quality index was,” Balmes said Friday afternoon. “In some of these polluted cities in Asia, people have air quality monitors in their homes and they calibrate what they’re going to do and whether they’ll wear a mask based on that monitor. We could very well be in that situation too.”

Erin Allday is a health reporter who writes about infectious diseases, stem cells, neuroscience and consumer health topics like fitness and nutrition. She’s been on the health beat since 2006 (minus a nine-month stint covering Mayor Gavin Newsom). Before joining The Chronicle, Erin worked at newspapers all over the Bay Area and covered a little of everything, including business and technology, city government, and education. She was part of a reporting team that won a Polk Award for regional reporting in 2005, for a series of stories on outsourcing jobs from Santa Rosa to Penang, Malaysia. Erin started her journalism career at the Daily Californian student newspaper and many years later still calls Berkeley her home.